1. Field of the Invention
This invention relates to a cyclic depsipeptide and a pharmaceutical preparation containing the same as an active ingredient. The cyclic depsipeptides of the invention have a promoting activity on the production of apolipoprotein E, an inhibitory activity on the production of apolipoprotein B and a promoting activity on the production of apolipoprotein A1. Since apolipoprotein E has a repairing activity for neurological damages, the present cyclic depsipeptides having a promoting activity on the production of apolipoprotein E are useful as a therapeutic agent for neurological damages, especially, dementia. On the other hand, apolipoprotein B is a main apolipoprotein of a low-density lipoprotein cholesterol (LDL cholesterol) known as the “bad” cholesterol and apolipoprotein A1 is a main apolipoprotein of a high-density lipoprotein cholesterol (HDL cholesterol) known as the “good” cholesterol. Thus, the cyclic depsipeptides of the invention having an activity of inhibiting the production of apolipoprotein B and an activity of promoting the production of apolipoprotein A1 are useful as a therapeutic agent for hyperlipemia.
2. Description of the Background
As a therapeutic agent for senile dementia, there have been mainly used activators of cerebral circulation and metabolism, but these drugs have no improving effect on disintegration of the central nervous system which is believed to cause senile dementia. Consequently, they possess no improving effect on dysmnesia and acalculia which are said to be central symptoms of dementia. In view of the above, there has been desired a new therapeutic agent for senile dementia which promotes the repair and growth of nervous systems while inhibiting the disintegration of the central nervous system.
On the other hand, it was reported that apolipoprotein E may be generated at a high level at the sites of nervous systems which were damaged and are being repaired (For example, refer to M. J. Igunatius, et al., Proc. Natl. Acad. Sci. U.S.A., 83, 1125 (1986)), which suggests that apolipoprotein E will play an important role in repairing nervous systems.